Patcheappan. S
2 Jun 2022
“Corpse is silent witness that never lies”
Content
1. Introduction
2. Medical examination a) External examination b) Internal examination
3. Types of incision
4. Techniques of Post-mortem
5. Collection of Biological samples for systematic toxicological analysis.
6. Estimation of time since death
7. Autopsy of HIV infected deceased.
8. Autopsy procedure: cleaning up.
1. INTRODUCTION:
Autopsy is a specialized scientific investigation of a cadaver (corpse), performed under the law, for the identification and prosecution of guilty. A forensic autopsy is also called a medicolegal autopsy [1]. Post- Mortem, dissection, pathological examination and necropsy are synonymous medical terminologies for Autopsy.
Autos = Self; Opis = view (to see for oneself)
Necros = dead; Opis = view
Post = after; Mortem = death
Why Post-mortem examination is needed?
1. To establish the identity of the individual.
2. To know the exact cause of death, whether the cause of death is unnatural, unexpected or unknown
3. To estimate the time since death
If a person dies and the death cannot be explained, an inquest may be held to establish the facts of the death, such as where and how the death occurred. An inquest is an investigation into the cause of death where death is apparently not due to natural causes. [2].
Classification of autopsy:
Autopsy can be classified into three types:
• Academic (done to learn the anatomy and pathological basis of human body by students).
• Pathological
• Judicial (Medico-legal autopsy)
Clinical autopsy and Medico-legal autopsy (autopsy done on authorisation). Autopsy is carried out for clinical as well as medico-legal purposes. Clinical autopsy, loosely termed as pathological autopsy, is carried out to diagnose the disease which has caused the mortality when ante-mortem efforts have failed (to evaluate the effects of treatment). Many a times clinical autopsy is done despite the cause of death having been established ante mortem, to study the disease process in situ, thus enriching medical knowledge. Medico-legal autopsy is performed with the aim of providing answers to questions about the identity, cause of death, time of death, circumstances of death, etc. thus helping the law enforcing agencies to solve the crime. The statutory enactment enables the state to order an autopsy in all suspicious and unnatural deaths. Medico-legal autopsies are systematic, objective, scientific and legally acceptable exercise. Although the procedure of both the categories of autopsies are same, they differ from each other in many aspects. Usually, the clinical autopsy is performed by the pathologist and medico-legal autopsy by a forensic expert. Medico legal autopsies do not require consent, whereas clinical autopsy requires consent of the relatives.
2. MEDICAL EXAMINATION
Medical Examination is the first thing done when the corpse arrives in the laboratory. The first thing the medical examiner does is an external autopsy; they look for clues on the outside of the body. This is done, because in most cases, what can be found on the outside can be more helpful than what can be found on the inside. Then, internal autopsy is done. The examiner looks at the internal organs to find out if he/she had a disease or damage [3].
A. External examination explained
1. Clothes - After examination for evidence of injury, struggle and stains, the clothes will be handed over to the investigating officer.
2. Features of identity (age, sex etc.,)
3. Blood stains, seminal stains, mud, foreign particles present on the body are described.
4. The Orifices (anus, ears, vagina, urethra, nostrils, and mouth) are examined for discharge, foreign bodies, injuries, other abnormalities.
5. Colour of nails
6. Evidence of sexual assault is looked for in female dead bodies.
a) Vulva and vagina
b) Hymen examined for recent/old tear
c) Vaginal swab collected and forwarded to chemical examiner to forensic science lab.
7. Injuries (ante-mortem/post-mortem) – nature, size, direction and edges of injuries
8. Post-mortem staining
9. State of rigor mortis / its distribution.
10. The degree of decomposition:
a) Greenish discolouration of right Iliac fossa (early decomposition Change). This is due to the formation of sulfhemoglobin facilitated by the commensal intestinal bacteria that invade the tissues after death.
b) Greenish discolouration of entire abdomen and chest.
c) Distension of abdomen
d) Marbling of skin.
e) Protrusion of tongue and eyeballs
f) Blood-stained froth at the mouth and nostrils
g) Blisters and peeling of cuticle
h) Bloating of face, neck, breast, penis, scrotum, and vulva.
i) Regurgitation of stomach contents.
j) prolapse of rectum and faecal discharge
k) prolapse of uterus and expulsion of foetus
l) Maggots (Flies lay eggs of death from 18-36 hrs, maggots or larva appear of death in 48-75hrs, pupae develop in 4-6 days, adult flies develop 6-10 days)
m) “Degloving” - A degloving injury is a type of avulsion in which an extensive section of skin is completely torn off the underlying tissue, severing its blood supply. It is named by analogy to the process of removing a glove.
n) Loosening of hair and nail
o) Colliquative putrefaction - During stage of Appearance of Maggots liquefaction of tissues (Colliquative Putrefaction) takes place. The tissues become soft, loose and are converted into a thick semi-fluid, black mass, to fall off separately, exposing the bones. The cartilage and ligaments are similarly softened. It usually commences on fifth day after death and is complete by tenth day.
p) Skeletonization: refers to the final stage of decomposition, during which the last vestiges of the soft tissues of a corpse or carcass have decayed or dried to the point that the skeleton is exposed.
11. Presence of adipocere (a greyish waxy substance formed by the decomposition of soft tissue in dead bodies subjected to moisture) / mummification looked for.
B. Internal examination explained:
1. Scalp is reflected and examined for injuries
A. Incision for removal of Cap
B. Saw-line for removal of Skull cap
2. The vault is examined for fracture. The type of fracture described.
3. The dura is examined for tear extradural haemorrhage and measured.
4. Subdural/subarachnoid spaces are examined for collection of blood /pus.
5. Appearance of the leptomeniges described
6. Brain removed
a) Signs of increased intracranial tension (Brain herniation) - flattening of gyri, obliteration of sulci, herniation of tonsillar part tentoria grooving.
Brain herniation is a potentially deadly side effect of very high pressure within the skull that occurs when a part of the brain is squeezed across structures within the skull. The brain can shift across such structures as the falx cerebri, the tentorium cerebelli, and even through the foramen magnum (the hole in the base of the skull through which the spinal cord connects with the brain). Herniation can be caused by a number of factors that cause a mass effect and increase intracranial pressure (ICP): these include traumatic brain injury, intracranial hemorrhage, or brain tumor.
a) Blood vessels are examined
b) The substance of brain is examined for softening injuries, haematoma, tumour, cyst and infection.
7. Mouth and pharynx are examined for injuries and presence of foreign bodies. Lips are everted and examined for injuries.
8. Neck structure including hyoid bone, thyroid and cricoid cartilages and tracheal rings are exposed and evidence of extravasation of blood, fracture and other injuries are looked for. The fracture of hyoid bone (abduction / adduction) noted.
9. Chest wall is exposed and injuries if present are described. Pneumothorax (collapsed lung) if suspected is tested before opening the chest wall.
10. Fluid/blood present in the chest cavities is measured.
11. The condition of diaphragm is noted and described.
12. Oesophagus opened and examined for presence of varices, corrosion and other abnormalities.
13. Air passage is exposed and examined for presence of soot, sand mud, weed, froth etc.
14. Lungs are examined with reference to weight, volume, consistency, congestion, oedema, natural disease, injury etc.
15. Contents of pericardial sac (measured/described)
16. Heart (examined in detail):
a) Weight
b) Condition of valves, walls and chambers
c) Coronaries (examined) by serially dissecting at 5mm intervals. Patency thrombus, atheroma, haemorrhage, occlusion of lumen. The entire heart is preserved in Formalin after dissection for microscopic examination when cardiac pathology is suspected.
d) The presence of air embolism / thrombo embolism looked for
e) Condition of aorta also examined.
17. Peritoneal cavity is exposed and its contents measured.
18. Liver, spleen, kidneys, pancreas, adrenals and intestines are dissected out and examined for evidence of natural disease, violence and poisoning.
19. Stomach is removed and dissected. The contents are examined and described as to the nature, degree of digestion etc. In most autopsies the contents of the stomach are an important piece of evidence, which can sometimes prove to be the difference between accidental death and foul play. The inspection of gastric contents must be part of every post-mortem examination because if the time of taking last meal is known, the approximate time since death may be calculated indirectly. It has been determined through extensive research that under ordinary circumstances the stomach empties its contents 4 to 6 hours after intake of meal.
3. TYPES OF INCISION
A plastic or rubber brick called a "head block" is placed under the shoulders of the deceased, hyper flexing the neck making the spine arch backward while stretching and pushing the chest upward to make it easier to incise. This gives the pathologist, maximum exposure to the trunk. After this is done, the internal examination begins. The internal examination consists of inspecting the internal organs of the body by dissection for evidence of trauma or other indications of the cause of death.
For the internal examination there are three approaches available:
1) Standard ‘I’ incision from chin to pubis: “I” Shaped Incision It starts from symphysis menti and extends straight to symphysis pubis right or left to umbilicus
2) ‘Y’ incision from mastoids to straight to pubis
3) Shoulder to manubrium sternili and then straight to pubis.
4. TECHNIQUES OF POST-MORTEM
The four major autopsy techniques differ chiefly in the methods used in removal of the organs and the order in which they are opened. Individual differences in the approach to the autopsy are generally only minor variations of one of the following procedures.
1. Virchow’s Technique: Each organ is removed separately one by one and then studied individually. This is done in the following order: expose the cranial cavity, the spinal cord, followed by the thoracic, cervical, and abdominal organs.
2. Letulle’s Technique: Removing all internal organs in single mass. Thoracic, cervical, abdominal, and pelvic organs are removed in masse and subsequently dissected into organ blocks. This is the best technique for preserving the vascular supply and relationships between organs. Another advantage is that the body can be made available to the undertaker quickly, without having to rush the dissection and risk obscuring findings or destroying important specimens. The major disadvantage is that the organ mass is often awkward to handle, and the autopsy is difficult to perform without an assistant.
3. Ghon’s Technique: Orga system are removed in organ block. Thoracic and cervical organs, abdominal organs, and the urogenital system are removed in functionally related blocks.
4. Rokitanski’s Technique: This procedure is characterized by in situ dissection.
5. COLLECTION OF BIOLOGICAL SAMPLES FOR SYSTEMATIC TOXICOLOGICAL ANALYSIS
The procurement of specimens is often the most important aspect of a good systematic toxicological analysis. The nature and integrity of the specimen(s) submitted for analysis usually determine the reliability and correctness of any toxicological result. After the first chance for collection has passed, it is frequently impossible to obtain a fresh sample of equivalent quality [4]. Hence, the International Association of Forensic Toxicologists' Committee on Systematic Toxicological Analysis strongly supports the collection of appropriate specimens in sufficient quantities to allow for a thorough and efficient approach to identifying unknown substances in biological specimens. Moreover, appropriate specimen selection and collection are critical for accurate and scientifically valid interpretation of analytical data, especially when the results are to be used in the judicial process [5].
6. ESTIMATION OF TIME SINCE DEATH
Meticulous autopsy not only provides information regarding cause and circumstances leading to death but also helps in estimating time since death. The interval between death and the time of examination of a body is known as post-mortem intervals.
How the time since death is calculated?
1. Changes in eye
Eyes loose lustre.
Corneal reflected is lost
Cornea becomes opaque’s due to drying
The pupil dilates at the time of death and later constrict with development of rigor mortis
Intraocular tension
Changes in vitreous humour
2. Cooling of cadaver – (temperature determined)
3. Cadaveric lividity discoloration of skin due to the accumulation of blood into the capillaries and small veins. The colour of post mortem stain is uniform.
4. Changes in muscle after death
• Algor Mortis (primary relaxation or flaccidity)
Algor mortis is the body temperature. After death, the body cools down at a certain rate until it reaches the surrounding temperature (body react to the external stimilai). During examination, thermometer is inserted into the liver to accurately measure the internal body temperature.
• Rigor Mortis (cadaveric rigidity)
Rigor mortis is the stiffening of the muscles. As time passes, the body will become stiff. Later, it will become so stiff that it won’t be able to be moved
• Livor Mortis (secondary relaxation)
This is the stage of disappearance of rigor mortis. Once the rigor mortis is passed off, the muscles become soft and flaccid contrary to primary relaxation. They do not respond to either mechanical or electrical stimuli. Discoloration of the body is seen at this stage. Lower areas will turn dark blue or purple, because that is where the blood settles.
5. Putrefaction or decomposition:
Putrefaction is a slow process of liquefaction due to digestive action of enzymes. Putrefactive changes usually occur following disappearance of rigor mortis, associated with the greenish discolouration of the abdominal skin and development of foul-smelling gases which forms blisters under skin. Marbling occurs 12 – 18 hours.
6. Adipocere changes: body converted into wax like substance.
7. Mummification occurs 3 weeks to weeks
8. Changes in bone marrow: Nuclei of neutrophils in bone marrow begin to well up
9. Examination of stomach content.
10. Examination of Intestinal content
11. Condition of urinary bladder.
12. Bio-chemical changes in blood. • PH value – falls • Chlorine level etc.
13. Changes in bone – radioactive carbon contents of bone decreases.
7. AUTOPSY IN CASE DECEASED IS AFFECTED BY AIDS
Viable HIV can be recovered from blood samples up to 16 days after death. Hence, the specimens to be properly labelled and filled with 10% of formalin solution. The body should be carefully washed with detergent solution and then with 0.5% hypochlorite solution before being finally rinsed with water. The body be placed in a double bag of heavy plastic which should be secured and tied properly at both ends. The body is red tagged as “HIV-RISK” and the relatives must be given strict instructions not to disturb the plastic-ware before cremation. If there is a known contagious organism the bag should be specifically labelled accordingly.
8. AUTOPSY PROCEDURE: CLEANING UP
It is up to the examiner performing the autopsy as to whether the organs that were removed are to be incinerated or to be replaced into the body. If they are to be replaced, the organs are typically kept in individual plastic bags and then placed back into the thoracic cavity. If the brain is to be replaced, it is placed back into the skull. Once the organs are within the trunk, the ribcage plate that was removed earlier is replaced. The skin of the abdomen and chest is then pulled back over the abdominal cavity and ribcage. The incisions are sutured with sturdy surgical thread.
For the skull, once the brain has been replaced into the skull, the calvaria is placed back on top. The skin flap that was pulled over the body's face is pulled back over the top of the head. The skin flap that was pulled down to the nape of the neck is also replaced. The incision will also be sewn up with surgical thread on the posterior side of the skull - therefore leaving no discernible scars when the body is shown in an open casket funeral. The skin will be cleaned with a sponge and running water. Afterwards, the body may be wrapped in a shroud (cotton material) and will the then handed over to the relatives.
REFERENCES
[1] Menezes RG, Monteiro FN. Forensic Autopsy. [Updated 2021 Sep 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK539901/
[2] Shrestha R, Kanchan T, Krishan K. Methods of Estimation of Time Since Death. [Updated 2022 May 15]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK549867
[3]Meslissa Conrad Stoppler, MD, Medicine Net, https://www.medicinenet.com/autopsy/article.htm
[4] Recommendations on Sample Collection, TIAFT-Bulletin XXIX - Number 1
[5] Eugene Tan, Sample Collection System for DNA Analysis of Forensic Evidence, NIJ Award 2008‐DN‐BX‐K010
Author S. Patcheappan is Assistant Public Prosecutor (APP), Puducherry